Topological Defects in Floquet Circuits

Fuente: arXiv
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Main Authors: Tan, Mao Tian, Wang, Yifan, Mitra, Aditi
Format: Preprint
Published: 2022
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author Tan, Mao Tian
Wang, Yifan
Mitra, Aditi
author_facet Tan, Mao Tian
Wang, Yifan
Mitra, Aditi
contents We introduce a Floquet circuit describing the driven Ising chain with topological defects. The corresponding gates include a defect that flips spins as well as the duality defect that explicitly implements the Kramers-Wannier duality transformation. The Floquet unitary evolution operator commutes with such defects, but the duality defect is not unitary, as it projects out half the states. We give two applications of these defects. One is to analyze the return amplitudes in the presence of "space-like" defects stretching around the system. We verify explicitly that the return amplitudes are in agreement with the fusion rules of the defects. The second application is to study unitary evolution in the presence of "time-like" defects that implement anti-periodic and duality-twisted boundary conditions. We show that a single unpaired localized Majorana zero mode appears in the latter case. We explicitly construct this operator, which acts as a symmetry of this Floquet circuit. We also present analytic expressions for the entanglement entropy after a single time step for a system of a few sites, for all of the above defect configurations.
format Preprint
id arxiv_https___arxiv_org_abs_2206_06272
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Topological Defects in Floquet Circuits
Tan, Mao Tian
Wang, Yifan
Mitra, Aditi
Strongly Correlated Electrons
Statistical Mechanics
High Energy Physics - Theory
Quantum Physics
We introduce a Floquet circuit describing the driven Ising chain with topological defects. The corresponding gates include a defect that flips spins as well as the duality defect that explicitly implements the Kramers-Wannier duality transformation. The Floquet unitary evolution operator commutes with such defects, but the duality defect is not unitary, as it projects out half the states. We give two applications of these defects. One is to analyze the return amplitudes in the presence of "space-like" defects stretching around the system. We verify explicitly that the return amplitudes are in agreement with the fusion rules of the defects. The second application is to study unitary evolution in the presence of "time-like" defects that implement anti-periodic and duality-twisted boundary conditions. We show that a single unpaired localized Majorana zero mode appears in the latter case. We explicitly construct this operator, which acts as a symmetry of this Floquet circuit. We also present analytic expressions for the entanglement entropy after a single time step for a system of a few sites, for all of the above defect configurations.
title Topological Defects in Floquet Circuits
topic Strongly Correlated Electrons
Statistical Mechanics
High Energy Physics - Theory
Quantum Physics
url https://arxiv.org/abs/2206.06272